Elastic band ligation device with locking mechanism and method for treatment of hemorrhoids

ABSTRACT

Elastic band ligation device for treating hemorrhoidal tissue, including an inner tube for retaining an elastic band, a plunger in the inner tube for drawing hemorrhoidal tissue into the inner tube, and an outer tube pusher sleeve disposed over the inner tube. A thumb pusher on the sleeve allows the operator to push the sleeve towards the front of the inner tube to deploy the elastic band from the front end of the inner tube onto hemorrhoidal tissue drawn into the inner tube. The sleeve has a locking mechanism including a tab for locking the sleeve to the inner tube to prevent relative movement of the sleeve and inner tube until the sleeve is unlocked by the user, thereby preventing premature deployment of an elastic band.

BACKGROUND OF THE INVENTION

The present invention relates to the treatment of hemorrhoids by elasticband ligation. More specifically the invention relates to an elasticband ligation device that is provided with a locking mechanism whichprevents premature elastic band deployment.

Commonly assigned patent applications entitled ELASTIC BAND LIGATIONDEVICE WITH ITEGRATED OBTURATOR AND METHOD FOR TREATMENT OF HEMORRHOIDS(U.S. application Ser. No. 13/972,144) and ELASTIC BAND LIGATION DEVICEWITH ANTI-PINCH FEATURE AND METHOD FOR TREATMENT OF HEMORRHOIDS (U.S.application Ser. No. 13/972,202) are filed simultaneously herewith, theentire disclosures of which are hereby incorporated by referenceherewith.

Treatment of hemorrhoids by elastic band ligation typically involvesplacing an elastic band on hemorrhoidal tissue in the rectum well abovethe “dentate line” (the junction of the sensitive squamous epitheliumknown as the “anoderm” and the insensitive lining of the rectum known asthe “mucosa”), where there is little sensation. The tissue trapped inthe band is cut off from its blood supply, degenerates and is sloughed,and the elastic band along with the sloughed tissue is passed with bowelmotions. More importantly, however, the resulting healing process causesthe tissue in the vicinity to become fixed, and prolapse of thehemorrhoidal tissue is minimized. This fixation of the tissue serves toeliminate the hemorrhoidal symptoms.

Many devices exist on the market utilizing the elastic band ligationtechnique. Examples are U.S. Pat. No. 5,203,863 to Bidoia, U.S. Pat. No.5,122,149 to Broome, U.S. Pat. No. 5,158,563 to Cosman and U.S. Pat. No.5,741,273 to O'Regan. The devices disclosed in U.S. Pat. No. 5,203,863to Bidoia, U.S. Pat. No. 5,122,149 to Broome, U.S. Pat. No. 5,158,563 toCosman are generally designed to be used in conjunction with aninstrument such as a proctoscope or anoscope to directly see the area tobe banded. In some cases, it is necessary to employ an assistant to holdthe proctoscope or anoscope. However, the use of these scopes, which aregenerally larger in diameter than banding apparatus, can causeconsiderable discomfort to a patient and more specifically to one who issuffering symptoms of hemorrhoids and other associated issues.

The device disclosed in U.S. Pat. No. 5,741,273 to O'Regan relates to anelastic band ligation device for treatment of hemorrhoids that may beused without directly seeing the site for banding. Thus, it may be usedwithout a proctoscope or anoscope or any other type of scope or viewingtechnique. Therefore, because the device can be inserted into the rectumand positioned appropriately without simultaneous visualization, or theneed for any type of scope, the banding procedure performed in thismanner causes less discomfort to the patient. This technique also allowsfor a more proximal placement of the elastic band, which increases thetechnique's efficacy as well as causing less discomfort and fewercomplications. This device has a suction device incorporated therein todraw hemorrhoidal tissue into an aperture for banding without requiringa second operator or connection to an aspirator.

Ligation is typically performed by initially inspecting the site througha small scope such as a sigmoidoscope, anoscope, proctoscope or othertype of scope and making a mental note as to the area where the bandshould optimally be placed. The scope is then removed and the ligationdevice is placed in the rectum. This is known as the “Blind” or “Touch”technique.

An alternative application is to visualize the area with an anoscope andinsert the banding through the lumen of the anoscope and band directly.This can be done if the operator prefers a direct visual approach. Thisis known as the “Trans-anoscopic” or “visual” technique.

The front end of the device is inserted well past the site for banding.Then, the device is gently withdrawn while it is pointed in thedirection of the anal canal, minimizing patient discomfort. As thedevice is being withdrawn, a palpable “ridge” on the outside of theouter tubular member is noted at the anal verge which can be used as aguide to the level where the band should optimally be placed in therectum. The device is then gently angled or “aimed” toward thehemorrhoid to be treated. In larger patients, the operator may choose toplace the device 1-2 cm further in through the anus prior to “aiming”the device towards the hemorrhoid to be treated.

However, it has been found that prior devices suffer from the drawbackthat the elastic band(s) may undergo premature deployment, with theresult that it is necessary to withdraw the device, recover the deployedelastic band within the rectum and begin the procedure again. This givesrise to delays and additional discomfort to the patient. From a patientand physician perspective, a quick smooth banding is most desirable. Onesituation that can prolong the treatment process is if the band isdeployed at the incorrect moment, leading to the need to re-load theband on the device. If this occurs when the device is inserted in thepatient, the discomfort to the patient is increased.

Currently the main cause for pre-mature band deployment is that thepusher (that pushes the band off the body of the ligator) can movefreely on its own as it is held with minimal frictional force on thedevice. If the pusher moves for whatever reason, the band can bedeployed at the incorrect moment. A need exists therefore for amechanism that would give the physician control over timing as to whenthe band is deployed. The general function of the device would remainthe same, thereby permitting training for existing users to berelatively quick. The present invention seeks to satisfy that need.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides an elastic band ligation device fortreatment of hemorrhoidal tissue comprising an inner tubular memberhaving a front end and a rear end, for retaining a stretched elasticband over the front end thereof, the front end having an opening, aplunger in the tubular member with a handle extending away from thefront end of the inner tubular member, the handle for sliding theplunger away from the front end of the inner tubular member to provide asuction for drawing hemorrhoidal tissue into the inner tubular memberthrough the opening at the front end, an outer tubular pusher sleeveconfigured to provide a limited friction fit over the inner tubularmember, with an external end of the outer tubular pusher sleeve adjacentthe stretched elastic band, and having an opposite end of the outertubular pusher sleeve provided with thumb push means for an operator topush the outer tubular pusher sleeve towards the front end of the innertubular member and release the elastic band from the front end of theinner tubular member to engage hemorrhoidal tissue extending through theopening in the inner tubular member, and an outer tubular pusher sleevelocking mechanism including a manually actuated tab connected to theouter tubular pusher sleeve for locking the outer tubular pusher sleeveto the inner sleeve to prevent relative movement of the outer sleeve andinner tubular member until the outer pusher sleeve is unlocked by theuser, thereby preventing premature deployment of an elastic band.

In another embodiment, the device may include an anti-pinch featurewhich reduces the risk of the patient's tissue being trapped as theobturator is retracted into the device.

In a further embodiment, the ligation device is made of plastic and isdisposable. Thus, once it has been used it is discarded and does nothave to be sterilized. In another embodiment, the ligation device ismade of metal and may be sterilized after each use.

The disposable elastic band ligation device of the invention may be usedin a doctor's office and does not generally require the administrationto the patient of any form of anesthetic. One to three elastic bands aregenerally placed at each patient visit and as many as six bands may berequired in total, particularly in advanced cases.

An obturator may be provided within the inner tubular member and may beconnected to the plunger. The obturator is typically integrally formedwith the plunger a single unit. The obturator is provided with a roundedsmooth end which may be induced to protrude beyond the front end of theinner tubular member by movement of the plunger. The purpose of theobturator is to facilitate access of the ligation device into the rectumof the patient with reduced discomfort to the patient, with minimaltraining of the physician, and with no requirement for the use ofadditional piece(s) of equipment.

In another embodiment, the ligation device of the invention may beprovided with a separable elastic band introducer device whichfacilitates introduction of the elastic band(s) onto the front end ofthe device. In one embodiment, the band introducer is in the generalshape of a cone and comprises a front tapered section, a rear sectiondimensioned such that it can be connected to the front end of the innertubular member, and a center section disposed between the front and rearsections having an external dimension corresponding to that of the frontend of the inner tubular member. The band introducer may be providedwith surface channels extending longitudinally to permit insertion of afinger(s) of the user below the band(s) to manipulate the band(s) ontoand/or off of the introducer. In use, the rear end of the introducer isconnected to the front end of the inner tubular member and an elasticband(s) is (are) rolled over the tapered front section and over thecentral section onto the front end of the inner tubular member. Once theband(s) has been placed on the front end of the inner tubular member,the introducer is removed prior to use of the ligation device.

An additional feature is the use, in the plastic version of the ligationdevice, of a plastic retention fixed ring on the inside of the proximalend of the inner tubular member for preventing the plunger from beingwithdrawn from the inner tubular member and thus preventing thepossibility of the instrument being cleaned and reused. Reuse of thedevice may be possible when the ligator is fabricated from metal, suchas stainless steel, which can be sterilized between uses.

A further feature, again in connection with the plastic version of theligation device, is the use of a treated slightly roughened insideplastic or a material such as Plexiglas SL7 on the inside of the innertubular member which turns opaque after attempted cleaning and, thus,provides a visual guide that the ligator has been used in one patientand should not be reused.

A yet further feature of the invention resides in a method of treatinghemorrhoidal tissue in a patient in need of such treatment. The methodcomprises the steps of: (a) providing an elastic band ligation device ofthe invention; b) applying at least one elastic band over the front endof the inner tubular member; (c) inserting the device carrying oneelastic band into the rectum of a patient; (d) adjusting the position ofthe device to arrange the opening at the end of the device to be indirect alignment with the hemorrhoidal tissue; (e) withdrawing theplunger to exert suction on the hemorrhoidal tissue and draw it throughthe opening into the inner tubular member; and (f) pushing the outertubular pusher sleeve to engage the outer tubular pusher sleeve againstthe elastic band to urge the elastic band onto the hemorrhoidal tissue;locking the plunger in place and allowing the engaged ligator to sit inorder to allow for more tissue to move inside the inner tubular member;and (g) the option of pushing the outer tubular pusher sleeve to engagethe outer tubular pusher sleeve against the elastic band, or to securethe outer tubular pusher sleeve while gently withdrawing the innertubular member which also engages the outer tubular pusher sleeveagainst the elastic band in order to urge the elastic band onto thehemorrhoidal tissue.

The device will typically be supplied to end users in the band loadingposition, that is with the plunger (and obturator if present) pulledback to allow the user to attach the band loading cone, push band(s)over and onto the main body of the ligator and remove the band loadingcone. Prior to insertion, the plunger is completely depressed, exposingthe smooth, rounded end of the obturator, which will help in thecomfortable passage of the ligator into the anorectum. Followinginsertion of the device into the anus of the patient, the plunger ispulled back to the “ready to draw material” position, which will be thesame location as the band loading position and will be marked by: aslight bump/feel in the plunger as in rides over a small detent/ringand/or a mark on the plunger that will align with the end of the ligatoror a line or mark on the ligator, and/or texture/color change that willdenote visually or by feel that the correct location has been reached.Tissue to be banded is located, and the plunger is pulled back to drawtissue into the inner tubular member until the inner ring is engaged.The device is oscillated 90 to 180 degrees in either direction to ensuretissue is captured properly. The band is deployed by either pushing thepusher forward or by securing the pusher and withdrawing the innertubular member until the band is deployed. The entire device is thenwithdrawn.

The term “a limited friction fit” as used herein means that the outertubular pusher sleeve exerts sufficient friction against the innertubular member such that the two components do not freely slide withrespect to each other but require gentle hand-applied pressure to moveone relative to the other.

In one embodiment, the ligation device is made of plastic and isdisposable. Thus, once it has been used it is discarded and does nothave to be sterilized. In another embodiment, the ligation device ismade of metal and may be sterilized after each use.

The disposable elastic band ligation device of the invention may be usedin a doctor's office and does not generally require the administrationto the patient of any form of anesthetic. One to three elastic bands aregenerally placed at each patient visit and as many as six bands may berequired in total, particularly in advanced cases.

In a further embodiment, the ligation device may be provided with anobturator within the inner tubular member. The obturator may or may notbe physically connected to the plunger. The obturator is provided with arounded smooth end which may be induced to protrude beyond the front endof the inner tubular member by movement of the plunger. The purpose ofthe obturator is to facilitate access of the ligation device wheninserted into the rectum of the patient.

An additional aspect of the invention provides a non-latex elastic bandfor use in the treatment of patients who exhibit or may exhibit a latexallergic reaction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of a first embodiment of ligationdevice of the present invention;

FIG. 2A is an enlarged side view of the of the outer pusher sleevelocking mechanism;

FIG. 2B is a cross-sectional view of the end of the device showing theend of the obturator partially protruding from the end of the device;

FIG. 3A is a perspective view of the outer pusher sleeve showing the tabof the locking mechanism and an enlarged inset view thereof;

FIG. 3B is a side view of the outer pusher sleeve;

FIG. 3C is a top view of the outer pusher sleeve;

FIG. 3D is a cross-sectional view of the outer pusher sleeve along theline 3D-3D in FIG. 3C;

FIG. 3E is a view from the distal end of the outer pusher sleeve;

FIG. 3F is a view from the proximal end of the outer pusher sleeve;

FIG. 4 is side view of the inner tubular member showing a locking ringon the outer circumference thereof;

FIG. 5A is a side view of an embodiment of the ligation device of theinvention showing the obturator extending from the end of the innertubular member and the outer pusher sleeve locking mechanism engagedwith the locking ring on the outer circumference of the inner tubularmember (an elastic band introducer is also shown adjacent the distal endof the device);

FIG. 5B is a view from the distal end of the device shown in FIG. 5A;

FIG. 6A is perspective view of the elastic band introducer showingsurface ribs and channels;

FIG. 6B is a side view of the elastic band introducer of FIG. 6A;

FIG. 6C is a cross-sectional view of the elastic band introducer alongthe line 6C-6C in FIG. 6B;

FIG. 7 is an side view of the device showing the locking mechanism onthe outer pusher sleeve;

FIG. 8 is a cross-sectional view of the device showing the obturatorpartially withdrawn inside the device;

FIG. 9 is a cross-sectional view of the device showing the obturatorfully withdrawn inside the device;

FIG. 10 is a cross-sectional view of the device showing the obturatorprotruding from the end of the device;

FIG. 11 is a cross-sectional view showing the elastic band introducer onthe distal end of the device;

FIG. 12 is a side view of an obturator;

FIGS. 13 and 14 are side views of an alternative embodiment showing adifferently shaped end for the obturator;

FIG. 15 is a cross-sectional view along line 15-15 of FIG. 14;

FIG. 16 is a cross-sectional view of the circled portion of FIG. 15;

FIG. 17 is a cross-sectional view of the circled portion of FIG. 16;

FIGS. 18 and 19 are side views of another embodiment showing adifferently shaped end for the obturator;

FIG. 20 is a cross-sectional view along line 20-20 of FIG. 19;

FIG. 21 is a cross-sectional view of the circled portion of FIG. 20;

FIG. 22 is a cross-sectional view of the circled portion of FIG. 21.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, FIG. 1 shows a first embodiment of a ligationdevice of the invention, generally referenced 2, comprising a plasticinner tubular member 4 having a convergent tubular section 6 with aninner surface 9 and an integrally formed straight cylindrical section 8.The convergent tubular section 6 has a rear end 10 and a front end 12for retaining a stretched elastic band 14 over the front end 12 thereof.

In the embodiment illustrated in FIG. 1, the inner tubular member 4 hasa convergent tubular configuration extending continuously from the rearend 10 to the front end 12 and for a sufficient distance to facilitateinsertion into the rectum of a patient.

A plunger 16 is slideably disposed in the cylindrical section 8, and hasa stem center section 18, a head 20 at one end of a stem section 18 anda handle 22 at the other end of the stem section 18 and extending awayfrom the front end 12 of the inner tubular member 4. The head 20 istypically fabricated from rubber and is adapted for sealingly engagingwith an inner wall of the cylindrical section 8. In the embodiment shownin FIG. 1, a sealing member 23 is mounted on the head 20 for sealinglyengaging with the inner wall 24 of the cylindrical section 8.

In the embodiment shown in FIG. 1, the plunger 16 is integrally formedwith an obturator 26 disposed internally of the inner tubular member.The obturator is provided with a rounded end portion 28 which bymovement of the plunger may protrude beyond the end 12 of the innertubular member, through opening 13, as shown in FIG. 1, or may bepositioned within the interior of the inner tubular member, as shown inFIGS. 8 and 9 (discussed below). The purpose of the obturator is tofacilitate access of the ligation device when inserted into the rectumof a patient.

The handle 22 permits the plunger 16 to be slid away from the front end12 of the inner tubular member 4 to provide a suction for drawinghemorrhoidal tissue into the inner tubular member 4 through the opening13 at the front end 12. The opening 13 may be slightly smaller indiameter than the inner tubular member 4. In another embodiment, thecylindrical section 8 and inner tubular member 4 may be separatecomponents joined together.

A plastic outer tubular pusher sleeve 30 is provided and a straightcylindrical section 32 and a tapering tubular section 34 correspondingto the taper of the convergent section of the inner tubular member 4.The outer tubular pusher sleeve 30 has a limited friction fit over thelength of the inner tubular member 4, and has an external end 36adjacent the stretched elastic band 14 and an opposite end 38 providedwith a locking mechanism 40.

The locking mechanism shown in FIG. 2A and generally referenced 40includes a tab 42 engageable with a locking ring 44 provided on theexterior surface of the inner tubular member 4. The locking ring has anabutment surface 48 extending at 90 degrees to the outer surface of theinner tubular member. The tab 42 is provided with a lug 46 whichprotrudes at 90 degrees from the tab 42 and abuts against the abutmentsurface 48, thereby preventing movement of the outer pusher sleevetowards the front end of the device. Upon pushing the tab 42 away fromthe inner tubular member 4, the lug 46 moves out of abuttingrelationship with the abutment surface 48 which allows the outer pushersleeve to be moved relative to the inner tubular member 4 towards thefront end of the device, thereby to push an elastic band off the frontend of the device onto hemorrhoidal tissue. The locking mechanism 40ensures that unintentional deployment of the elastic band as a result ofmovement of the outer pusher sleeve towards the front end of the devicedoes not occur until the outer pusher sleeve is unlocked by the user.

Device would be supplied to end user with the lock engaged such that theband pusher would not move. User would; attach loading cone, load bandand lubricate as normal. Insert device and locate tissue. Pull back onplunger until lock ring is engaged, oscillate to confirm bite ofmaterial is correct. (lock feature would not prevent band pusher fromoscillating freely relative to the ligator main body) Slight pressurewould be applied to the band pusher thumb flange, the angle of the thumbflange would cause the release of the teeth engaged/locked. Band pusherproceeds forward to release and deploy the band. Band pusher can bepulled back to re-engage the mechanism (to keep contaminated devicetogether) Plunger pushes forward to release material and device isremoved.

Final amount of engagement needs to be determined, when engaged a staticload of 2 lbs would be desirable. Final angle of thumb flange to clearengagement needs to be determined. An audible click would be desirableto confirm engagement however dis-engagement would however be preferablynear silent.

FIG. 2B shows in cross-section the distal end of the inner tubularmember end 4 with the end 28 of the obturator partially protruding fromthe opening 13. The outer surface 11 of the end 28 is convergent towardsthe distal tip of the obturator, creating an angle of 5-25 degreesbetween the outer surface 11 of the obturator end 28 and the innersurface 9 of the inner tubular member 4. This feature serves to reducepinching of tissue when the obturator 26 is moved relative to the innertubular member, particularly when the obturator is withdrawn into theinner tubular member 4. This anti-pinch feature allows gaps to increaseas components move together, or allows for no gap as they move together,thereby minimizing the risk of pinching of tissue as the end of theobturator emerges from or is retracted into the inner tubular member 4.In the illustrated arrangement, pinching is reduced as the pinch areaincreases allowing material to move away freely. As indicated in FIG.2B, the angle between the outer surface of the end 28 and the innersurface of the inner tubular member is typically in the range of 5-25degrees, for example 5-10 degrees, and is typically about 30 degrees orless.

FIG. 3A shows the tab 42 and the lug 46. Cut-outs 47′ and 47″ areprovided to permit adjustment to tune the force required to deflect thetab 42 away from the inner tubular member. The highest force would be aconfiguration with no cut-out, decreasing in force as the cut-outsdeepen and widen.

FIG. 3B is a side view of the outer pusher sleeve 30 and FIG. 3C is atop view of the outer pusher sleeve 30. FIG. 3D is a cross-sectionalview of the outer pusher sleeve 30 along the line 3D-3D in FIG. 3C andFIG. 3E is a view from the distal end of the outer pusher sleeve 30.FIG. 3F is a view from the proximal end of the outer pusher sleeve 30.

FIG. 4 shows the inner tubular member 4 with the locking ring 44disposed on the outer circumference thereof. The shape of the lockingring is shown in greater detail in FIG. 2A.

FIG. 5A shows a circumferential ring marker 50 provided on the externalcircumference of the outer tubular pusher sleeve 30. This serves as adepth marker to the user with regard to the extent of insertion of thedevice into the rectum of the patient. FIG. 5A also shows the obturator26 protruding from the end of the inner tubular member. FIG. 5B is aview from the distal end of the device shown in FIG. 5A.

FIGS. 6A-6C show views of the elastic band introducer 60. FIG. 6A isperspective view of the elastic band introducer 60 showing surface ribs61 and channels 63. FIG. 6B is a side view of the elastic bandintroducer of FIG. 6A and FIG. 6C is a cross-sectional view of theelastic band introducer along the line 6C-6C in FIG. 6B. The taperedsurface 65 of the introducer 60 facilitates loading of elastic bandsthereon by rolling the bands onto flat region 67 of the introducer priorto pushing the bands onto the inner tubular member 4.

FIG. 7 shows a side view of the device showing the locking mechanism 40and cut outs 47′ and 47″. In the embodiment shown, the locking mechanism40 is engaged with the locking ring 44 on the inner tubular member 4.

FIG. 8 is a cross-sectional view of the device showing the obturator 26partially withdrawn inside the inner tubular member 4, and FIG. 9 is across-sectional view of the device showing the obturator 26 fullywithdrawn inside the inner tubular member 4. FIG. 10 is across-sectional view of the device showing the obturator 26 protrudingfrom the end of the inner tubular member 4.

FIG. 11 is a cross-sectional view of the elastic band introducer 60 onthe distal end of the inner tubular member 4 whereby the end of theinner tubular member 4 is received within slot 69 of the introducer 60.In this way, elastic band(s) 14 loaded on the flat region 67 can berolled onto the outer surface of the inner tubular member downstream ofthe distal end of the outer tubular pusher sleeve 30.

FIG. 12 is a side view of a combined plunger 16 and obturator 26 for usein the device of the invention. As noted earlier, the plunger andobturator may be separate items or may be integrally formed in onepiece, as shown in FIG. 12. The rounded end section 28 facilitates morecomfortable access of the ligation device into the rectum of a patient.

FIGS. 13 and 14 are side views of an alternative embodiment showing adifferently shaped end for the obturator 26. In this embodiment, thedistal end of the obturator has a region of reduced diameter 26′ towardsthe tip to further facilitate entry of the device into the rectum of thepatient and to reduce the incidence of pinching of tissue as theobturator is withdrawn into the device after deployment of a band ontothe hemorrhoidal tissue.

FIG. 15 is a. cross-sectional view along line 15-15 of FIG. 14. FIG. 16is a cross-sectional view of the circled portion of FIG. 15 showing ingreater detail the region 26′ of reduced diameter towards the obturatortip.

FIG. 17 is a cross-sectional view of the circled portion of FIG. 16showing an alternative embodiment whereby a flexible anti-pinch wiperelement 70 suitably of a thin plastics material is connected to, orintegrally formed with, the end of the inner tubular member 4. Theflexible anti-pinch element 70 is disposed such it abuts against theouter surface of the end of the obturator and prevents tissue from beingtrapped or pinched between the outer surface of the end of the obturatorand the inner surface of the inner tubular member 4.

FIGS. 18 and 19 are side views of another embodiment showing adifferently shaped end for the obturator. In this embodiment, the end 72has parallel walls 74 rounded at 76 at the tip of the obturator, whichreduces the incidence of pinching of tissue.

FIG. 20 is a cross-sectional view along line 20-20 of FIG. 19. FIG. 21is a cross-sectional view of the circled portion of FIG. 20 showing ingreater detail the region the configuration of the obturator tip 72.

FIG. 22 is a cross-sectional view of the circled portion of FIG. 21showing a further alternative embodiment whereby a flexible anti-pinchwiper element 80 suitably of a thin plastics material is connected to,or integrally formed with, the end of the inner tubular member 4. Theflexible anti-pinch element 80 is disposed such it abuts against theouter surface of the end of the obturator 72 and prevents tissue frombeing trapped or pinched between the outer surface of the end of theobturator 72 and the inner surface of the inner tubular member 4.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. An elastic band ligation device for treatment ofhemorrhoidal tissue, comprising: an inner tubular member having an innersurface, an outer surface, a front end and a rear end, for retaining astretched elastic band over the front end thereof, the front end havingan opening, the inner tubular member extending for a sufficient distancefor insertion into a rectum of a patient; a plunger in the inner tubularmember with a handle means extending away from the rear end of the innertubular member, the handle means for sliding the plunger away from thefront end of the inner tubular member to provide a suction for drawinghemorrhoidal tissue into the inner tubular member through the opening atthe front end; an outer tubular pusher sleeve having an innerconfiguration corresponding to that of the inner tubular member toprovide a limited friction fit with the outer surface of the innertubular member, with an external end of the outer tubular pusher sleevepositionable adjacent a stretched elastic band; a locking mechanismprovided at an opposite end of the outer tubular pusher sleeve forlocking the outer pusher sleeve and the inner tubular member to preventmovement of the outer tubular pusher sleeve towards the front end of theinner tubular member, said locking mechanism comprising a tab formed insaid opposite end of said outer tubular pusher sleeve, a locking ringpositioned on said outer surface of said inner tubular member, saidlocking ring having an abutment surface which extends outwardly from theouter surface of the inner tubular member towards the tab, said tabhaving a lug extending transversely from the tab towards the innertubular member and into engagement with said abutment surface to preventmovement of the outer tubular pusher sleeve towards the front end of theinner tubular member, said tab when pressed in use disengaging the outertubular pusher sleeve from the inner tubular member and allowing theouter tubular pusher sleeve to be moved towards the front end of theinner tubular member and into contact with the elastic band to urge theelastic band away from the front end of the inner tubular member andinto engagement with hemorrhoidal tissue extending through the openingin the inner tubular member; said outer pusher sleeve further comprisingcut-outs adjacent the tab for permitting adjustment to tune a forcerequired to deflect the tab away from the inner tubular member.
 2. Theelastic band ligation device according to claim 1, wherein upon pushingthe tab away from the inner tubular member, the lug moves out ofabutting relationship with the abutment surface which allows the outertubular pusher sleeve to be moved relative to the inner tubular membertowards the front end of the device, thereby to push an elastic band offthe front end of the device onto hemorrhoidal tissue.
 3. The elasticligation device according to claim 1, wherein a circumferential ringmarker is provided on an external circumference of the outer tubularpusher sleeve as a depth marker to a user with regard to an extent ofinsertion of the device into the rectum of the patient.
 4. The elasticligation device according to claim 1, further comprising an elastic bandintroducer for facilitating introduction of elastic bands onto the innertubular member.
 5. The elastic ligation device according to claim 4,wherein the elastic band introducer has a tapered region and a flatregion.
 6. The elastic ligation device according to claim 5, wherein theelastic band introducer has surface ribs and channels extending alongthe tapered region.
 7. The elastic band ligation device according toclaim 6, wherein the introducer has a slot in the flat region whichreceives the distal end of the inner tubular member.
 8. The elastic bandligation device according to claim 1, further comprising an obturatordisposed within the inner tubular member.
 9. The elastic band ligationdevice according to claim 8, wherein the obturator and the plunger areintegrally formed.
 10. The elastic band ligation device according toclaim 8, wherein an outer surface of an end of the obturator isconvergent towards a distal tip of the obturator and creates an angle of30 degrees or less between the outer surface of the obturator end and aninner surface of the inner tubular member.
 11. The elastic band ligationdevice according to claim 10, wherein the angle is 5-25 degrees.
 12. Theelastic band ligation device according to claim 8, wherein a distal endof the obturator has a region of reduced diameter towards a tip tofacilitate entry of the device into the rectum of the patient and toreduce pinching of tissue as the obturator is withdrawn into the deviceafter deployment of the elastic band onto the hemorrhoidal tissue. 13.The elastic band ligation device according to claim 8, wherein aflexible anti-pinch wiper element material is connected to an end of theinner tubular member and abuts against an outer surface of an end of theobturator to prevent tissue from being trapped or pinched between theouter surface of the end of the obturator and an inner surface of theinner tubular member.
 14. The elastic band ligation device according toclaim 13, wherein the wiper element is flexible and is made of a thinplastics material.
 15. The elastic band ligation device according toclaim 1, wherein an end of the obturator has parallel walls rounded at atip of the obturator, to reduce pinching of tissue.